Ryan Fitzpatrick lofted a rainbow high into the Florham Park sky, and Brandon Marshall caught it in stride down the left sideline past Dexter McDougle.

“That was the best deep ball he’s ever thrown me,” Marshall said.

One play was all it took to fill the first day of Jets summer with hope and ignite a “J-E-T-S! JETS! JETS! JETS” chant from fans under the VIP tent.

The bearded journeyman quarterback, with the new one-year, $12 million contract, reunited with the big, relentless machine of a wide receiver, each of them betting on himself in part because they believe so much in the other.

Fitzpatrick threw for 3,905 yards last season, and 1,502 of them were to Marshall. Fitzpatrick threw 31 touchdowns last season and 14 of them were to Marshall, ever so sleek at 224 pounds after being as high as 244 over the offseason.

On Thursday, Marshall challenged wondrous Steelers receiver Antonio Brown on Instagram to a receiving yards competition: If Marshall wins, he’ll receive Brown’s Rolls-Royce, and if Brown wins, he’ll get a green-and-white Jets-themed Porsche from Marshall that was parked at the team’s facility. Brown accepted.

“I’ve had a unique career where I’ve played with eight different quarterbacks and been really blessed to be in position to always make plays, and put up a lot of stats, so that’s never been an issue for me,” Marshall said. “But it does make it easier when you have a guy like Ben Roethlisberger. It makes it easier to catch 140 balls.”

A British bookie has made Brown a 1-3 favorite with Marshall getting 5-2 odds. There were no odds posted on whether Roger Goodell might feel compelled to take it off the board. Told that he was the underdog, Marshall smiled and said: “Oh yeah, of course. Big Ben is one of the best quarterbacks ever.”

Brandon MarshallBill Kostroun

I said to Marshall: “You’re putting some heat on Ryan now.”

“Yeah, I went to Ryan, I said, ‘Look at this right here. I’m just giving you a heads up,’ ” Marshall said.

Fitzpatrick, who had to text Marshall for his door code to get into the building and make it in time to the team meeting Wednesday night, is betting he can come close to replicating his career 2015 season and proving to doubters even within the Jets facility that he is nobody’s backup mentor just yet.

“I’ve got a ton of confidence in myself,” Fitzpatrick said. “When that [three-year] offer came in, all I thought to myself was, ‘We’ve got to do it as a one-year deal,’ because if that’s how they see it, I’d much rather bet on myself.”

He is 33, a year older than Marshall. Neither has been to the playoffs. Both are immensely prideful men.

“I would almost not want them to sign a guy that they offered that contract,” Fitzpatrick said. “How could I look myself in the mirror in the morning and say, ‘Yeah I’ll try to play good this year and then next year, I’ll just collect some checks and teach the young guys?’ It’s not who I am, it’s not my nature.”

When last we saw him, he was standing behind a podium outside the visiting locker room in Buffalo shouldering the blame for his fourth-quarter implosion that threw away a shot at the playoffs.

It didn’t help his negotiating position.

“That quarter of football didn’t make things easier for sure,” Fitzpatrick said.

It didn’t make the start of the offseason easier for him, either.

“It eats at you a little bit,” Fitzpatrick said. “That was tough, it was a tough game all around, but you move on. Fortunately and unfortunately, I’ve had plenty of quarters like that where you’ve just got to get over it and move on, and sometimes, it’s in the middle of a game, sometimes you got to sit and dwell on it all offseason. That’s part of playing quarterback.”

If Fitzpatrick wins his bet, and Marshall wins his, the Jets will have a real shot at breaking the Patriots’ seven-year stranglehold on the division, especially with Tom Brady saddled with his four-game Deflategate suspension. Fitzpatrick isn’t thinking about the Pats just yet. He’s thinking about the loyal men he will be leading again.

“I got to go out and perform for all the guys in the locker room,” Fitzpatrick said.

“Internally, in this building, there’s a lot of guys that are counting on me.”

Probably none more than Marshall.

“I told him, I said, ‘Bro, it looks like you’re just playing golf out there,’ ” Marshall said. “It’s just so easy, his rhythm, he’s not rushing anything, forcing anything. I thought he had a really great day.”

Fitzpatrick did throw a pair of interceptions and was understandably a bit rusty. You saw Christian Hackenberg sidle up alongside him and act as a sponge when Geno Smith ran a drill.

Fitzpatrick will be an invaluable resource in the quarterbacks room. Marshall, asked about the reaction when Fitzpatrick walked back into their Jets lives, smiled and said: “Business. Let’s go win some games. You won all this money. You better throw some touchdowns.”